You cant - Articuno is a legendary and the only way to get it again is to start another game or cheat. When catching legendarys, always save just before you fight them, and if they faint, switch the power off without saving.
*Articuno It's hidden in the Seafoam islands, which you can swim to west of Cinnabar.
I assume you're talking about Articuno. To get Articuno you have to go to the Seafoam Islands, which is on route to Cinnabar Island.
Yes, it is possible to skip the Seafoam Islands. It's not a required area in the game; you can go there to catch Articuno, which you don't need to do to complete the game.
You can catch Articuno on seafoam island whenever you don't have to beat the Pokemon League.
On Seafoam Islands.
seafoam islands
Inside Seafoam Islands.
Seafoam islands.
you get articuno in seafoam islands
Seafoam Islands.
seafoam islands
*Articuno It's hidden in the Seafoam islands, which you can swim to west of Cinnabar.
I assume you're talking about Articuno. To get Articuno you have to go to the Seafoam Islands, which is on route to Cinnabar Island.
Articuno can be found in Seafoam Islands just talk to it and you will battle it.
In the Seafoam Islands, east of Cinnabar Island. You need HM Waterfall, though.
seafoam islands
in the seafoam islands in kantobottom of seafoam island